T43p LCD replacement

[mitchW]

I recently acquired a broken T43p (2668-Q1G).
The machine had stationary vertical and horizontal lines on the whole LCD (15.1'' FlexView UXGA), and the indicator lights on the inverter weren't working. But on the external display, it was working perfectly (Video Card Stability Test for 3 hours), so I think a bad GPU can't be the case. Therefore I examined the mobo and found blown F8 fuse. Replacing it corrected the problem with indicator LEDs, but the LCD problem was still present.

So next, I got two replacement 15.1'' UXGA LCDs, one of them was from an A31p (FRU: 05K9967, model IAUX14S), another one was generic (HannStar HSD150PU13). I tried both of them, but none of them showed any picture, only black screen with backlight on. The A31p's LCD wasn't tested before, but I tested a HannStar one with a R60 one year ago -- that one worked okay. Next, I tried a LCD from R51 (15.1'' XGA) that worked, but the picture was split in half and not correctly displayed -- like it was getting an UXGA signal, and not XGA as it should receive. Also, I tried all of LCDs with a R51 LCD cable, but they all acted in the same way, so bad cable is also out of question. The original display is Hydis HV150UX1-100, FRU: 13N7076.

Therefore, I am asking why none of these two monitors work? Perhaps is there any EEPROM or EDID that needs to be reprogrammed for a particular mobo to accept a different monitor? I am really on to repair this machine, as it is one of the fastest and beefiest T43p machines I ever got hands on. Also it is in near mint condition.

Any suggestions are welcome!

[RealBlackStuff]

It pays to read through some of the more popular threads on this forum.
By doing so, you would have come across one of the umpteen posts like this:
The graphics chip (GPU) has two outputs, one digital for the internal LCD and one analog for the external monitor.
One can work fine (usually the external/analog one) while the other (usually the internal/digital one) does not work properly (and gives garbled output as in your case).
Remedy: either professional reballing of the GPU (available in the UK) or replacing the motherboard.

[ajkula66]

I will tell you that an A31p screen works out of the box on T43p, with the T43p cable and inverter.

No need for re-programming anything.

I'd still suspect a problem with the board...

[mitchW]

A friend of mine, who does professional reballing (done about 1000 laptops) suggested that I heat up the chip with an temperature adjustable heatgun that I own, but just barely (around 200 deg. C). If the LCD then works, he will reball the mobo, if not, I can try again with around 10-20 degrees higher temperature, to see if it helps. Also he suggested, that there could be a problem with LCD driver chip.
Also, as I have written, the A31p LCD is untested, as it was pulled from a broken machine, so it may or not work at all. I have tested the original LCD (Hydis) on a R51, and it also showed lines, so it is definitely shot. Other two UXGA LCDs behaved exactly the same way on R51 (black picture) as on the TP43p, but I believe that this is because R51 has an Intel video card, and it cannot output UXGA. The XGA of course worked like a charm on R51.

[ajkula66]

OK we've got too many eggs in the basket and it's getting confusing...

When you plug the XGA LCD from R51 using the LCD cable from it as well into the T43p planar, what do you get?

[mitchW]

OK we've got too many eggs in the basket and it's getting confusing...

When you plug the XGA LCD from R51 using the LCD cable from it as well into the T43p planar, what do you get?

I get recognizable picture (POST screen), but distorted -- it only shows top part of the picture, and very vertically distorted. Like someone zoomed on top third of the screen.

Also, new update, I have heated the chip with heatgun, but there is no change whatsoever. I went up to 230 deg. C.

[ajkula66]

I get recognizable picture (POST screen), but distorted -- it only shows top part of the picture, and very vertically distorted. Like someone zoomed on top third of the screen.

Also, new update, I have heated the chip with heatgun, but there is no change whatsoever. I went up to 230 deg. C.

OK now you can most definitely kiss that board goodbye and start shopping for a replacement one.

[RealBlackStuff]

Your GPU is definitely the cause.
You could ask your friend to reball it, using leaded balls rather than RoHS required unleaded balls.
The leaded balls definitely make better contact than unleaded ones, and withstand heat cycles a lot better.
But it is doubtful that your "home-cooking" has kept your board still fixable.